Dubai Metro

Our laminated elastomeric bearings have been approved and used as Temporary bearings for launching pads as well as Permanent bearings for rail tracks. Click images to get more details on Dubai Rail Project

Palm Jumerah Mono Rail Project

Another feather on our hat

Laminated Elastomeric Bearings and sound proofing elastomer floorings for Palm Jumerah Mono Rail Project were supplied by us.

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Welcome to Pretread.com, your reliable source for ..neoprene bridge bearing, bearing pads, laminated elastomeric bearing, elastomeric bearing,.. moulded rubber products, precure tread rubber, tread liner,ptfe Teflon sliding,ptfe Teflon sliding, ptfe ptfe Teflon pipe supports, molded rubber products, rubber gaskets, and rubber marine fenders. Our home page and connected links provide information on a wide range of rubber products.

Why use laminated elastomeric rubber bearings for Bridges and buildings ?

A bridge basically consists of bridge deck supported by piers. In order to avoid damage by movements of thermal expansion, vehicular movement, loading to piers,bridge bearings are used to accommodate these movements so as to reduce reaction forces and bending movement to within safety limits of structure. Neoprene as well as Natural Rubber is an ideal engineering material for bridge bearings as it is highly elastic and sufficiently soft to accommodate these movements without transmitting harmful stress and also it absorbs and isolates energy from impacts and vibrations. Bridge bearings are devices for transferring loads and movements from deck to piers.

Pretread.com is direct manufacturer of Laminated Neoprene Bridge Bearings and Laminate Elastomeric Bearings, ptfe Teflon sliding bearings. We at pretread.com, manufacture neoprene bridge bearings, elastomeric, pads, high damping rubber bearing, expansion joints, PTFE sliding bearing, sliding bearings to AASHTO / BS / DIN specifications for the first time in the Middle East U.A.E. Laminated elastomeric bearings, bridge bearings, bridge bearing pads high damping bearing pads are manufactured mostly in neoprene elastomeric compounds.

Types of Bearings manufactured by us.

Plain and Laminated elastomeric bridge bearings

We manufacture plain and laminated elastomeric bearings for construction industry in neoprene and natural rubber compound confirming to BS/AASHTO/DIN standards. Bridge bearings and bridge bearing pads are manufactured in ..neoprene rubber compounds,.. unless other wise specified for natural rubber compound. Our specialization is in neoprene bridge bearings, elastomeric, pads, high damping rubber bearings are from our years of experience, and with support from our technical and marketing partners.

Laminated Bearing designing

Let us verify ..load calculations.. for your bearings. On receipt of corbel size, load and movement details of your requirements, calculations and bearings sizes can be provided based on results on parameters compared to AASHTO LRFD - FREE.

ptfe- Teflon sliding bearings

TEFLON sheets are used as sliding top surface on top of laminated elastomeric bearings and manufacture ptfe Teflon sliding bearing in combination with SS 316 Grade Stainless Steel mirror finished surface as sliding top proves excellent sliding control. Thickness of ptfe TEFLON sheets will be to AASHTO / BS / DIN / En 1337-2 specifications. We are proud to be the first one in the Middle East in U.A.E.to provide such manufacturing facility, with ptfe Teflon, there by high cost of import and time delay can be avoided.

Bearing design AASHTO M 251 - 06

Bearing design sheet confirming to AASHTO LRFD

Bearing design EN 1337 - 3 - 2006

Bearing design sheet confirming to EN 1337-3:2005

Lead Rubber Bearings (HDRBL)

A lead-rubber bearing is a laminated elastomeric bearing with a lead plug down its center.

The rubber/steel laminated bearing is designed to carry weight of structure and provide post-yield elasticity and lead core deforms plastically under shear deformations. Its size can be selected to produce the required amount of damping and benefits in using lead-rubber bearings for base-isolation:

Lead-rubber bearing are sufficiently stiff so that vertical loads and small lateral loads can be carried without excessive deformations occurring. Indeed, for small lateral loads (e.g., less than 0.1g ground acceleration) base-isolated and fixed-base structures should exhibit very similar behavior.

The size of lead plug is proportional to yield strength of isolator. The post-yielding stiffness is proportional to rubber bearing stiffness, and increases with plan size of the rubber bearing and reductions in the isolator height. During severe seismic attacks, however, the lead plug is capable of deforming through many low-cycle plastic deformations without a loss of strength occurring.

High Damping Rubber Bearing (HDRB)

As an alternative to the lead rubber bearing,we offer high damping rubber bearing (HDRB) which is ideal for seismic isolation with one device - supporting the structure, providing elastic restoring force and also required amount of damping up to a maximum of 10-15% of critical. Moderate damping is achieved with this type of bearing.

The HDRB isolation bearings are vertically stiff, capable of supporting vertical gravity loads, while being laterally flexible, capable of allowing large horizontal displacements. In effect, the ground is allowed to move back and forth under a base isolated during an earthquake, while leaving building to remain "stationary." By means of its flexibility and energy absorption capability, with HDRB rubber bearings isolation system partially reflects and partially absorbs some of the earthquake input energy before this energy can be transmitted to the structure. The net effect is a reduction of energy dissipation demand on structural system, resulting in an increase in its serviceability.

Significantly reductions of structural and non-structural damage may be achieved through the use of HDRB rubber bearings seismic isolation. Reduction in elastic-force reductions by factors of 5- to 10- are possible. Expressed in simple terms with regard to building performance, this is roughly equivalent to a reduction of a Richter-magnitude-8 event to an event in the 5-to-6 magnitude range. Clearly, this is a very significant reduction. These potential benefits are greatest for stiff structures fixed rigidly to ground, such as low- and medium-rise buildings, nuclear power plants, bridges and many types of equipment. Some of the heady duty bearings supplied by us and installed in structures in Pakistan has helped to minimize damages to the structure as will as human life.

Recent disasters caused in many parts of the world have due to earthquake has made many structural designer to start using with HDRB rubber bearings base isolation systems to building and structures. We have few Projects in hand are very keen to work on such Projects and you are requested to contact us.

Ptfe sliding bearings.

We offer both ptfe (Teflon) sliding pads as well as Teflon sliding bearings. Ptfe Sliding bearing pads can be used for lower loads and Sliding Bearings (with laminated bearing or carbon steel backing alone)for higher loads. Both ptfe Teflon sliding, Teflon Sliding bearings as well as sliding bearing pads are supplied with appropriate thickness SS 316 mirror finished plates with mild steel backing plates for low friction coefficient ptfe pipe supports.

Ptfe sliding bearings can be manufactured both in rectangular and disc type. Modern day construction requires large span movements for buildings and www.pretread.com has the solution for you. Especially in constructing Shopping Malls and buildings with large spans with movements over 100 mm movements, effective and economical solution is to use our ptfe Teflon sliding bearing combination with laminated neoprene elastomeric bearing and as ptfe pipe supports.

Ptfe Teflon Sliding bearing strips.

Neoprene based plain bearing strips are used in low load low shear movement slabs. But with current requirements of large movements to these low load beams to meet seismic movements we offer neoprene bearings strips with ptfe teflon as sliding surface and a Stainless Steel mirror finished sheets and sliding top plates.

Ptfe Teflon pipe supports

In application as pipe supports, PTFE Slide Bearings are superior to conventional expansion plates, rollers and rocker arm type supports. Ptfe Teflon pipe supports, accommodate expansion, contraction and other reciprocating motions of any structure that moves as a result of thermal expansion, Seismic or differential forces. Laminated Bearings for pipe support applications must operate at high loads and low speeds, and under these both conditions the self-lubricating properties of PTFE are exposed to maximum. This factor, together with its no stick-slip and anti-weathering characteristics, is the principle reason on why PTFE has proved to be so successful as a slide bearing material.

Advantages of ptfe sliding pipe supports.

The simplicity of the bearing design and its ease of fabrication and installation make the unit cost efficient. The costs of a construction can be reduced by designing for expansion rather than strain. Coefficient of friction over the bearing surface remains constant, even under worst case conditions. bearings are maintenance free - PTFE is inherently self - lubricating, while dirt particles are absorbed into the material. Only simple protection is required against the significant increases of dirt.

Dimpled Virgin ptfe -Teflon sheet is hot bonded to CS ( carbon steel ) base plates using proprietary hot bonding method at temperature of 160 º C or above and at a pressure of 250 Kg /cm² which provides much higher peel-off strength between CS plate and ptfe - long service life. Surface irregularity formed during long term sliding movements reported between SS plate and ptfe-Teflon under varying vertical load seen in conventional pipe supports is totally avoided with dimpled ptfe-Teflon with silicon grease - long service life. High melting point Silicon grease applied between dimple ptfe-Teflon and top SS 316 plate will stay in dimples to provide a Lower friction coefficient between ptfe - Teflon and SS316 - long service life. Ptfe-Teflon offered will be of European origin with necessary certifications - quality assurance.

Design / Selection of ptfe sliding pipe supports.

AARP offers a specialist service, based on many years experience in the use of PTFE and its application to slide bearings to assist in the design of bearing systems. Low friction sliders with coefficient of friction less than 0.1 are available. They are designed specifically for the loads and movements required. Most assemblies are also designed to be compatible with our range of standard sliders and glides, Also 'stand alone' Slide Bearing Sandwich Plates are available. ptfe Teflon sling bearing assemblies AARP Slide Bearings consist of a single PTFE pad hot bonded to MS plate which can be welded to plate supports and the top polished to mirror finished stainless steel plate to slide over it. The assembly is designed to ensure that the PTFE pad is covered by the S/S plate throughout the expected design movements. The basic element is a 2.5 mm PTFE sheet, hot bonded to 4 to 8 mm mild steel backing plate for straight forward field installation by welding. Where operating conditions require them, thermal insulation and vibration damping pads may be bonded between the PTFE sheet and the backing plate as plain neoprene pads or in some cases as laminated elastomeric bearings to be installed between the backing plate and the structure. To allow operation at high ambient temperature, a hot bonding system is used for bonding, and the adhesives are cured under strictly controlled conditions, of 140 degrees C and 200 Kg pressure to ensuring that the bond is stronger than the PTFE itself. Usually such bonding is carried out in a special hydraulic press As standard glass filled PTFE as well as black filled ptfe also is used as the bearing material, where much higher bearing loading as well as lower deformation under loads are required.

ARP-NEOSLIDEPAD

Building structural design has taken a considerable change over the last decade. The sizes of spans have grown bigger, difference of internal and external temperature has become greater and global warming has changed climatic changes. These factors have exerted great demand on elastomeric bearing design and requirements. New polymer types and combinations with Stainless Steel have paved way for new designs. Thus we offer a combination of elastomeric bearing with ptfe known as ARP-NEOSLIDEPAD for PTFE sliding bearing requirements.

ARP-NEOSLIDEPAD - (PTFE Sliding bearing system with Stainless Steel Top and Neoprene Protective Seal) are specially designed, manufactured and assembled with a combination of polyamide or steel reinforced neoprene bearing pad with PTFE top and a SS 316 L plate sliding over top as a whole unit protected with a soft neoprene seal.

Bearing Installation

General information on installation of bearings are available from Installation - Bridge Bearings and will provide bearing installation procedure on laminated bearing pot bearings as well as ptfe Teflon bearings.

Warranty on Laminated Elastomeric bearings manufactured and supplied by us.

Though Neoprene Rubber , Natural Rubber and ptfe PTFE- Teflon has been non bio-degradable over last 50 years, a warranty is given for limited years for Laminated Elastomeric Bearings./ Pot Bearings /ptfe Teflon sliding bearings manufactured and supplied by us provided these Bearings are chosen for appropriate load /movement and utmost care is taken during the time of installation on placement.

Bearings designed/ manufactured and supplied by us are based on Technical Information on Vertical Load, horizontal movements, horizontal load, etc provided by Client, Consultant, Bridge Designer. Any variations to above forces, movements in excessive to a higher value during time of installation as well as service, can damage these bearings permanently and such damages does not cover our warranty and will not be responsible for any other financial loses caused by such damage.

Instaltionof Bearings

Our Engineering team will provide you with complete assistance for instalation of all kinds of bearings. Please email us with your requirements.

Other rubber products manufactured by us.

In addition to neoprene bridge bearing, bearing pads, laminated elastomeric bearing, elastomeric bearing,.. moulded rubber products, precure tread rubber, tread liner,ptfe Teflon sliding,ptfe Teflon sliding, ptfe ptfe Teflon pipe supports, molded rubber products, rubber gaskets, and rubber marine fenders. tire retreading equipment,ptfe Teflon sliding moulded rubber products, molded rubber, shock absorber mountings, molded rubber products etc.

Our quality assurance.

We are the first and only laminated bearing manufacturing facility in Middle East to have an in-house bearing testing facility to carry out tests confirming to AASHTO specification in accordance with Acceptance Testing on either Level I or Level II as well as Short/Long-Duration Compression Test. Our bearing testing machine can test bearings up to Vertical load of 10000 kN with horizontal shear load up to 400kN and movement up to 100 mm.

Under one roof with stringent quality control, with technical and marketing support from our Technical Partners we manufacture neoprene bridge bearings, ptfe pipe supports, laminate elastomeric bearings, bearing pads, pot bearings, PTFE sliding bearings etc to AASHTO / BS / DIN specifications.

This web site has a wealth of information on our product lines and general information which we try to updated quite often. We hope you will find our site very informative and will contact us for further details and inquires. Click on below link, to obtain regular archive on our site.